1. Field of the Invention
The present invention relates to a process for producing polyalkenyl ether.
2. Related Background Art
Conventionally, polymers of alkenyl ether have been attained from cationic polymerization. In cationic polymerization, transfer and termination usually tend to occur easily, rendering it difficult to form a polymer or block copolymer having a narrow molecular weight distribution. However, Higashimura, Sawamoto et al. discovered the following matters relating to the use of an initiator consisting of HI and I2. That is, they discovered that alkenyl ethers allow living growth, and, that alkenyl ethers can form a polymer or block copolymer having a narrow molecular weight distribution (Macromolecules, Volume 17, 1984, p. 265-268).
Higashimura, Aoshima et al. further discovered a synthesis process for cationic living polymerization of such alkenyl ethers from a Lewis acid and an added base (Polymer Bulletin, Volume 15, 1986, p. 417). Other known examples include an HCl/SnCl4 system (Macromolecules, Volume 26, 1993, p. 744 and “Macromol. Symp.,” 85, p. 33-43, 1994) and an HCl/ZnCl2 system (Macromolecules, Volume 25, 1992, p. 2587).
According to such cationic living polymerization processes, a macromolecule compound having a variety of repeating unit structures can be attained by conducting polymer synthesis. In other words, polyalkenyl ether polymer such as a homopolymer and a copolymer consisting of two or more monomer components, as well as a block copolymer, graft polymer and gradient polymer can be attained. Furthermore, it is now becoming possible to synthesize these polymers having a degree of polymerization controlled to a certain extent of precision. However, the fact still remains that further improvements in living polymerization are required in order to expand the degree of freedom of polymer molecule design and increase productivity through improvements in polymerization rate and controllability.
In particular, when polymerizing alkenyl ether represented by the following general formula (I):CHR1═CH(OR2)  (I)wherein R1 represents a hydrogen atom or a methyl group, R2 represents a monovalent organic group, and R2 contains a silicon atom or at least one atom selected from the group consisting of elements from group 15 to group 17, a considerable amount of time is required. It is thus desired to shorten this polymerization time.